Flex中的CSS： （3）CSS会被编译器转换为什么样的AS代码--组合：

解说：

s|Button#btn,.MyStyle 这种用逗号分隔形式的CSS定义体实际上是多个定义的组合。即

s|Button#btn

{。。。}

.MyStyle

{。。。}

?这种形式的定义称为：组合

?

test1.mxml

<?xml version="1.0" encoding="utf-8"?>
<!-- styles/SelectorsTest.mxml -->
<s:Application 
	xmlns:fx="http://ns.adobe.com/mxml/2009" 
	xmlns:mx="library://ns.adobe.com/flex/mx" 
	xmlns:s="library://ns.adobe.com/flex/spark">    
	<s:layout>
		<s:VerticalLayout/>
	</s:layout>
	
	<fx:Style>
		@namespace s "library://ns.adobe.com/flex/spark";
		@namespace mx "library://ns.adobe.com/flex/mx";
		
		s|Button#btn,.MyStyle{
			font-size:20px;
		}
		
	</fx:Style>
	
	<fx:Script>
		<![CDATA[

			public function showSelectors():void {            
				
				var selectors:Array = styleManager.selectors;
				msg.text = "所有的选择器列表如下(" + selectors.length + ")n";
				for (var i:int = 0; i < selectors.length; i++) {
					msg.text += "n" + selectors[i];      
				}
			}
		]]>
	</fx:Script>    
	<s:Group id="group1" width="511" height="396">
		<s:TextArea id="msg" x="1" y="28" width="100%" height="359"/>
		<s:Button id="btn" label="Show Selectors" click="showSelectors()"/>
	</s:Group>
	
	<s:Group id="group2" width="511">
		<s:Button label="test" click="showSelectors()"
				  styleName="MyStyle"/>
	</s:Group>
</s:Application>

执行结果：

?

编译器自动生成代码：

        var conditions:Array;
        var condition:CSSCondition;
        var selector:CSSSelector;
        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("id","btn");
        conditions.push(condition); 
        selector = new CSSSelector("spark.components.Button",conditions,selector);
        // spark.components.Button#btn
        style = styleManager.getStyleDeclaration("spark.components.Button#btn");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.fontSize = 20;
            };
        }




        selector = null;
        conditions = null;
        conditions = [];
        condition = new CSSCondition("class","MyStyle");
        conditions.push(condition); 
        selector = new CSSSelector("",selector);
        // .MyStyle
        style = styleManager.getStyleDeclaration(".MyStyle");
        if (!style)
        {
            style = new CSSStyleDeclaration(selector,styleManager);
        }

        if (style.factory == null)
        {
            style.factory = function():void
            {
                this.fontSize = 20;
            };
        }

?

?

可见，这种形式定义的CSS和分开定义的结果是完全相同的。